Problem: Vanessa ate 3 slices of pie. William ate 2 slices. If Vanessa ate $\dfrac{3}{9}$ of the pie, what fraction of the pie is remaining?
Solution: If 3 slices represent $\dfrac{3}{9}$ of the pie, there must have been a total of 9 slices. $\text{fraction of pie remaining} = \dfrac{\text{number of slices remaining}}{\text{number of slices total}}$ Together they ate 5 slices, which leaves 4 out of 9 slices remaining. There is $\dfrac{4}{9}$ of the pie remaining.